Soil movement may have caused sinkholes

KUALA LUMPUR: Soil movement or high water pressure may have led to the bursting of pipes that caused the recent series of sinkholes in the city.

Pengurusan Air Selangor Sdn Bhd (Air Selangor) has begun investigating the three sinkhole incidents that occurred in less than 48 hours and has so far identified several likely factors.

“One of them is the movement of soil caused by vibrations or hard pounding. This is usually the case when the pipes are near construction sites or are just beneath the road surface,” said corporate communications head Abdul Halem Mat Som in a statement yesterday.

“Soil movement can also happen when it rains. The flow of rainwater erodes the soil holding the pipes in place and they break,” he added.

“Pipes can also burst if they cannot handle high water pressure, especially in the case of old asbestos cement pipes.”

He confirmed that there were no injuries from the incidents and that repair works at the affected areas were completed yesterday.

The three sinkholes were in Jalan Maharajalela, Jalan Pinang and Jalan Dewan Bahasa, which are all within the city centre.

They were caused by damage to the pipes that are part of Air Selangor’s water distribution system.

Air Selangor, Abdul Halem said, had also taken measures to avoid such incidents in the future.

“For Jalan Maharajalela, Air Selangor will carry out redistribution of water pressure until it reaches an optimal level,” he said.

This was done, he added, by installing an endcap on the pipe at the side of the road and carrying out tapping relocation for 10 premises receiving water from the affected pipeline.

“For Jalan Pinang and Jalan Dewan Bahasa, Air Selangor has installed a pressure logger to analyse the pressure profile and stabilise the water supply system in the area,” he said.

He added that Air Selangor also carried out valve control and pressure monitoring measures.

Pointing out that the asbestos cement pipes in front of Dewan Bahasa dan Pustaka were more than 30 years old, Air Selangor said its long-term plan was to replace ageing pipes.

“Air Selangor has identified 438km of asbestos cement pipes to be replaced, and to date, 365.16km of the pipes have been replaced,” he said.

Abdul Halem said Air Selangor and Kuala Lumpur City Hall were discussing the issue of compensation for the damage of vehicles.

The National Water Services Commission (SPAN) said it had instructed Air Selangor to monitor other high-risk areas that are prone to sinkholes.

“This is to avoid the same incident from occurring again, especially during the rainy season which is expected to last until February next year,” it said in a statement yesterday.

SPAN noted that investigations by Air Selangor showed that the three sinkhole incidents could be due to the use of old asbestos cement pipes and soil movement due to vibration and rainwater.